Photochemical method for preparation of benzo[a]pyrano[3,2-c]phenazin-4-ones from quinoxalines with 4-pyranone unit

Photochemical properties of terarylenes with quinoxalines bridge unit and allomaltol fragment was investigated. We have demonstrated that starting compounds with hydroxyl group in 3-hydroxy-4-pyranone substituent does not undergo any photoinduced transformations. Wherein, conversion to methoxy derivatives allows one to realize photochemical 6π-electrocyclization for considered quinoxalines. Based on data of x-ray analysis the observed difference in reactivity is connected with the presence of hydrogen bond in hydroxyl derivatives. As a result of carried out research photochemical approach to novel benzo[a]pyrano[3,2-c]phenazin-4-ones was implemented.